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United 2,996,506 PIPERAZINE DERIVATIVES Philippe Gold-Aubert, Geneva, Switzerland, assignor to Laboratoire Sapos, Geneva, Switzerland, a Swiss body corporate No Drawing. Filed June 16, 1958, Ser. No. 74%033 Claims priority, application Great Britain June 25, 1957 8 Claims. (Cl. 260468) (in which R and R which may be the same or different, are hydrogen atoms, alkyl groups containing from 1-5 carbon atoms, unsaturated aliphatic groups such as ally-l or vinyl groups or aryl or aralkyl groups, -Al=k and -Alk are alkylene chains containing from 1-3 carbon atoms whichmay be straight or branched and which may be the same or different and R R R and R which maybe the same or different, are hydrogen atoms or alkoxy groups containing from 1-3 carbon atoms) and their non-toxic salts.

Preferred compounds according to the invention are those in which Alk and Alk are CH CH and the compound N,N'-di-( S-phenylethyl-acetyloxyethyl) piperazine dihydrochloride has been found to be especially useful. Examples of non-toxic salts of the stated com pounds are the hydrohalides, sulphates, phosphates, citrates, lactates, acetates etc. and of these the dihydrohalides are preferred.

Other compounds according to the invention which are of special interest are shown in the following table:

TABLE V Alk.=l1k R1=R nz=R R R 1 4.5

-CH-CHz- -C:H5 H H 250 (511:; i ilij 8%.51'13233333333: E 11 iii -CH:CHn CHzCHCHs H H 228 3H3 SEZEE II iiiitIIII: E 5 iii T'CHPOHP.- --CHCH3 H H 220 1 g Y 7 t The compounds of the present invention possess a strong atropinic effect but possess marked advantages over atropine. In particular they have little or no eflfect on salivation or intestinal secretion such as is produced by atropine, and thus on administration produce little or no drying of the mouth, or diarrhea or vomiting. In addition the new compounds further possess some antihistaminic activity but on the other hand prolong the hypotensive effect of histamine. They possess a spasmolytic effect similar to that of papavarine and have some anti-emetic action. The new compounds also show marked anaesthetic properties, the infiltration anaesthetic effect of the compound N,N'-di-(/S-phenylethyl-acetyloxyethyD-piperazine dihydrochloride being greater than that of xylocaine although its contact effect is slightly less than that of cocaine. At the same time they have been shown to have a low toxicity and to be capable of absorption from the gastro-intestinal tract.

The new compounds of Formula I may be prepared by reacting compounds of formula K-N N-J II with compounds of formula I Il -@CH-C 0. L

1'2 III where R, R and R have the meanings stated above and 'as an alkali metal carbonate or bicarbonate, e.g. sodium and potassium carbonates and bicarbonates.

Alternatively, J and K may represent hydrogen atoms,

or the system -H.H O, and L may then represent a group of the formula --AlkHal where Hal represents a halogen atom such as chlorine. This reaction may be carried out in the presence or absence of solvents. Solvents which may be used for the reaction include for example benzene or dioxan.

Again the groups I and K may represent the group -(Alk) Hal, where Hal represents a halogen atom such as chlorine and in this case L may be the group OM where M represents a hydrogen atom or an alkali metal such as sodium or potassium. The reaction is preferably carried out in the presence of an inert solvent for example anhydrous benzene and in the presence of an acid binding agent, for example, anhydrous potassium carbonate.

It will be apparent that variations and extensions of the methods outlined above are possible, enabling further variations in the substituents to be obtained. Thus, iftwo different compounds of Formula III are reacted with a compound of Formula II a mixture of compounds of Formula I will result in which R, R and R are not necessarily the same as R R and R respectively.

Further, compounds of Formula I may be prepared in which R and/or R are hydrogen atoms and, since such hydrogen atoms will be activated by the adjacent phenyl and ester groups, the compounds may be reacted subsequently with appropriate halides, such as alkyl halides, to produce other compounds of Formula I in which *"R and R are other than hydrogen and may be different if desired. Such a reaction may be carried out in an alkaline medium such as alcoholic sodium ethoxide.

In order that the invention may be fully understood 7 the following examples are given by way of illustration benzene and 1 6.8 of sodium bicarbonate and 17.5

gm. phenylethylacetyl chloride run in dropwise with stir ring. After heating for four hours with continued stirfiltering and recrystallising the precipitate from water ring and then leaving overnight the precipitate of sodium three times, one obtained N,N'-di-(fi-p-chlorophenylethchloride is filtered 01f, and the solution dried over anylacetyloxyethyl)piperazine dihydrochloride M.P. 218" hydroussodium sulphate. The sodium sulphate is then C. removed and dry hydrochloricacid gas passed through 5 Example 5 the dried benzene solution until the dihydrochloride'has 14 hen 1 eth lacetc acid, 12 N,N -d1- -chloro- Preclpltated 1 P i 'd1.7(fi7phcny1ethyl' acc" ethylfipigeraz ine dihydr ochloride 15.5 g. anhyii i ous potylqxyethyl)'pl.peraz.me dlhydmclflonde may be News 1 tassium carbonate and 30 mls. ailhydrons benzene were talllsed, after isolationby filtration, from alcohol/ether heated for 18 hours with Stirring in a flask provided with or acetone E I 72 a stirrer and cooling means. 50 mls. Water at 40 -C. xamp I were then added with stirring to dissolve the precipitated 45.3 (2 mols.) phenylethylacetyl-B-hydroxyethyl potassium chloride and the base extracted with benzene. chloride are heated with 8.6 gm. 'piperazine at 120 C. On acidifying N,N-di-({3-phenylethylacetyloxyethyl)-pifor several hours. The resultingproduct is dissolved perazine dihydrochloride was obtained; M.P. 223 C. in hot ethanol and caused to crystallise by cooling and E xample 6 adding ether oracetone.

8.7 g. (0.05 mol) of N,N-di-(B-hydroxyethyl)-piperazine were mixed with 18.2 g. phenylethylacetyl chloride 10.1 g. mole) of N,N'43-hydroXypr0pyl-piperazine in a cooled flask. 30 cos. of anhydrous ether were added. were dissolved in 100 dioxan in a vessel provided with a 20 The mixture was heated under reflux for'hal-f an hour stirrer and cooling means and 8.4 g. sodium bicarbonate and then left to stand at room temperature for 24 hours. added. 1.8.25 g.iphenylethylacetyl chloride were then The dihydrochloride was thusformed directly. Before added drop by drop with stirring; heated for a further filtering off the solid obtained it Was verified that all smell 6.hours underreflux with stirringand allowed to stand of acid chloride had disappeared. The solid obtained overnight. The next day, 10 mls. concentrated HCl dis- 25 was dissolved in 95% ethanol and allowed to crystallise. solved in 10 mls. water were added, thetemperature In general three recrystallisations from ethanol were broughtto 15 C., the NaClprecipitate'filteredoff and necessary to obtain a completely white product. The the product extracted with ether. After concentration 1 crystals were washed with ether. M.P. 220 C. and crystallisation followed by recrystallisation from I claim: 7 alcohol/ ether there was obtained N,N- di-(B-phenylethyl- 1. As new compounds, compounds of the formula Example 3 W YP PYD-P P dihydlochlolide, 7 50 in which R and R are members selected from the group C, i r v 40 consisting of a hydrogen atom, an alkyl group containing Example 4 1 to 5 carbon atoms, an allyl group and a vinyl group, 7 .2 g. l N y piPeraZine and All; are members selected from the group conwere dissolved in.l00 rnls..anhydrousbenzeneinfla flask slstmg of a Stralght alkylene 'f p CQntBJ-Umg 1 provided-with. stirrer,- cooling means and a .droppinglfunto 3 93.113011 atoms and a branched ch31? y g l; nel. After adding7 g. sodium. bicarbonate, .18 Y g'. of contammg 1 to 3 carbon atoms; and R R and R p-chlorophenylethylacetyl chloride were added. dropwise, e membfils Selected from the group conslstmg Of a yand the mixture heated for a further 4 hours undersreflux dr gen atom, a chlorine atom and an alkoxy group conwith good stirring and'left overnight. The next day'the taining 1 to 3 carbon atoms; and their non-toxic acid sodium chloride was filtered off, dissolved idwater, exaddition salts. tracted with benzene andthis benzene extract, dried 'over 2. The compound having the formula sodiumsulphate together with the benzene filtrate; After 3. A non-toxic acid addition salt of the compound of evaporation-to dryness under vacuum-the base'was re claim}. 7 dissolved in 100 mls. alcohol and 20' mls. ether and a v 4. The compoundhavmg theformula .-cnoo.0-om-cn-N N -CtL-OHQ-dQg-uHQ 231115 JIH: I, 7 7 i s strong stream of HCl (dried over H passed through 5. A non-toxic acid addition salt of compound of until the pH fell to 3. The-temperature-rose and then a 7 claim 4. precipitate formed. After cooling in the refrigerator 6.";The compound having the formula mQom-coo-crrr-c FN n-ronronrooo-on. -o1

7. The compound having the formula 8. The compound having the formula C3H7 C3H7 References Cited in the file of this patent Pyman: J our. Chem. Society (London), pp. 1802-1803 (1908).

Zaugg et 411.: Jour. Amer. Chem. Soc., vol. 7-2, pp. 3004-3007 (1950). 

1. AS NEW COMPOUNDS, COMPOUNDS OF THE FORMULA 